PATTERNS AND RISK-FACTORS FOR SPRAINS AND STRAINS IN ONTARIO, CANADA 1990 - AN ANALYSIS OF THE WORKPLACE HEALTH AND SAFETY AGENCY DATA-BASE

This study presents the results of analyses performed to generate hypo theses concerning the general patterns of risk factors for occupationa l sprains and strains, using Ontario workers' compensation data housed in the Workplace Health and Safety Agency (WHSA) data base. Historica lly, the largest percentage of lost-time injuries In Ontario, Canada, have been sprains and strains. In 1990, there were 171,047 compensated lost-time injuries with a known nature of injury, of which 50.43% wer e sprains and strains. From cross-tabulations, a number of statistics such as odds ratios (ORs), 95% confidence intervals, P values, attribu table risks end number of injuries attributable. were calculated. Resu lts indicate that occupational sprains and strains are related to the time of tile day and, in particular, time into the workshift. They occ ur more frequently than expected (based on the occurrence of non-sprai n and non-strain injuries) in the morning hours and in the first 4 hou rs of the workshift. They are not found to be related to the starting or ending time or the length of the workshift. They occur more frequen tly than expected during the early part of a week, especially on Monda ys, and the early part of a year (January to May). With respect to age , workers 30 to 59 years old have an increased risk of sprains and str ains, whereas workers less than 30 years of age, or 60 or more years o f age, have a decreased risk. Workers who are not single, and female w orkers, have a higher risk of sprains and strains than expected. With respect to occupations, nurses and truckers have a higher-than-expecte d risk. A number of work environments and activities, such as overexer tion, bodily reaction from involuntary motions, running and stretching and slippery surfaces, are associated with a high risk of occurrence of sprains and strains. These results suggest that significant reducti on, in, tile number qi occupational sprains and strains could be achie ved by targeting prevention programs to reduce excess risks encountere d in the first 4 hours of the workshift, on Mondays, and during the fi rst 5 months of the year, and by workers 30 to 59 years of age, female workers, and nurses and truck drivers. It is estimated that, with pro per interventions to avoid sprains and strains, a large percentage of sprain and strain injuries could be avoided each year: ie 82.49% of in juries due to bodily reaction from involuntary motions, 89.43% of over exertions in lifting objects, 84.64% of running, stretching, and relat ed injuries, and 76.64% of injuries resulting from loss of balance on slippery surfaces. This study uses an internal comparison, ie comparin g the risk of sprains and strains to the risk of all other injuries fo r various risk categories of interest. As a result, an increased OR ma y mean an increased risk of sprains and strains, or it may mean a decr eased risk of all other injuries for a particular risk category. There are also limitations in the use of workers' compensation data base fo r epidemiologic studies. Therefore, findings in this study are only su ggestive for further investigations and should await confirmations bef ore prevention programs are designed.